Photo of the Week. The Earth's shadow rises over the
sea after sunset.
Astronomy news for the two weeks starting Friday, November 20,
2015.
The next skylights will appear December 4, 2015.
With first quarter passed the night
of Wednesday, November 18, the Moon starts our session in the waxing gibbous phase, which fattens until
it hits full phase on Wednesday the 25th just
about the time of Moonrise in North America. It then switches to
the waning gibbous, which fades until
third quarter is passed the morning
of Thursday, December 3, again about the time of Moonrise. We
close out the fortnight with a bit of the waning crescent.
The evening of Tuesday the 24th, the rising Moon will appear to
the right of the Pleiades,
the following night to the west of Aldebaran. With the Moon moving
its own angular diameter in an hour, by the morning of Thursday
the 26th, it will cross over, or occult, the bright star, the
event visible from Canada and the northern US (starting 4:44 AM
CST for Chicago). Those to the south will see the Moon go north of
Aldebaran. "Visible," however, is problematic as the Moon will be
just past full and far brighter than the star. It will be far
easier to watch the Moon slip below Leo and Jupiter. The morning of
Tuesday the 1st the Moon will be directly west of Regulus, while the following night
it will fall below the star. The quarter Moon then appears to the
southwest of Jupiter the morning of Thursday the 3rd and then passes a
couple degrees south of the giant planet shortly before Moonrise,
by which time the Moon will be also slightly east of Jupiter,
the pair making a fine sight. The Moon passes perigee, where
it is closest to Earth, on Monday the 23rd.
With Saturn going
through conjunction with the Sun on Sunday the 29th and Mercury lost in western twilight, the
evening sky is devoid of the ancient planets, those known since we
first looked upward. The morning sky, however, makes up for that
lack. Jupiter rises first, about 1 AM as our period opens, near
midnight as it ends, Mars
(brightening into first magnitude) about an hour and a half
later. The pair is followed by unmistakably-bright Venus shortly before 3 AM, the trio parading across the sky
until sunup. If you have the time, try to follow Venus into
daylight. Even Jupiter has been seen with the naked eye in a
clear blue sky. Venus will appear a few degrees north of Spica in Virgo the morning of Thursday the 26th.
Orion is coming strongly onto
the nightly scene, the seven-starred Hunter well up by late
evening with the reddish supergiant Betelgeuse at the upper left
corner, the three-star Belt to
the southwest of it, the closely-spaced trio as unmistakable in
its way as Venus. With the Belt closely marking the celestial equator, Orion serves to
divide the northern celestial hemisphere from the southern. While
from northern lands we get to see the whole northern celestial
hemisphere, much of the good stuff is in the south. From mid-US
latitudes, anything south of 50 degrees below the equator is cut
off by the horizon, rendering the southern Milky Way, the Southern Cross, and our biggest galactic satellites,
the two Magellanic Clouds, quite
invisible.
